Method for manufacturing base member, method for manufacturing motor, method for manufacturing information apparatus, and base member, motor, and information apparatus

ABSTRACT

If a blank is mistakenly supplied to a precision machining apparatus corresponding to the wrong model, the missupply can be detected early on by a simple method. 
     A method for manufacturing a base member, which is a method for manufacturing a base member on which a plurality of members are mounted, in which a plurality of kinds of material are machined according to a machining program that differs for each material, said method including the following steps.
         A preparation step of providing a display portion with a different shape for each type of material   A machining step of machining the material according to a machining program   A machining operation step of performing an operation for machining the display portion as part of the machining step, and thereby making it possible to determine whether or not the material has been machined in the proper combination according to the corresponding machining program

This application claims priority under 35 U.S.C. §119 to Japanese PatentApplication No. 2008-51153 filed on Feb. 29, 2008. The entire disclosureof Japanese Patent Application No. 2008-51153 is hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a base member on which a plurality ofmembers are mounted, and to a method for manufacturing this base member,and further relates to a motor, an information apparatus, and methodsfor manufacturing them.

2. Background Information

For example, a hard disk drive (HDD) comprises a spindle motor, arecording disk attached to the spindle motor, a head for reproducingdata from the recording disk or recording data to the recording disk,and an actuator for driving the head.

The spindle motor and actuator of a hard disk drive are mounted on abase plate. The base plate is, for example, a member obtained bysubjecting a blank obtained by aluminum die casting to precisionmachining with a machining center or the like. Structures are formed inthe base plate, such as the shape of ribs provided to the blank, theattachment portion of the actuator, and the screw portion for componentattachment, and the shape of these structures vary with the model of thehard disk drive. The reason is that the specifications of the attachedcomponents vary with differences in the number of disks, the rotatingspeed, the intended application, and so forth.

Meanwhile, between models of the same form factor (such as 2.5-inch)from the same hard disk drive manufacturer, the shapes are very similar,making it difficult to tell at a glance the difference between theshapes of the above-mentioned structures. Consequently, a blank issometimes accidentally supplied to a machining center corresponding to adifferent model. When this happens, the blank ends up being precisionmachined by a machining program corresponding to a different model. Insuch a case it is hard to notice that the product is irregular, and thisaccidentally machined base plate may continue on to the next productionline without being detected. This can result in the base plate ending upin a completed hard disk drive, and may not be detected until theshipping inspection step. As a result, after the shipping inspectionstep, the completed product has to be discarded or reassembled.

Therefore, a mark is formed to identify the model of the base plate. Forinstance, there is a known technique whereby a plurality of displayholes indicating a manufacturing die number are formed in a base plate(see Japanese Laid-Open Patent Application 2001-101777, for example).However, with the technique discussed in Japanese Laid-Open PatentApplication 2001-101777, there is the risk that the base plate strengthand hermetic seal will be diminished. To solve this problem, there isalso a known technique in which a base plate is provided with aplurality of coded protrusions, or letters are written in relief todisplay the model name, etc.

When a model name or the like is coded and written in relief on a baseplate, the model name is determined by image recognition technologyusing an image recognition apparatus prior to precision machining.However, noise tends to be picked up due to the effects of surfaceirregular reflection or the like, and solving this problem requires fineadjustment of the image recognition apparatus. Also, in the case ofletters, misrecognition is inevitable because of factors such asblurring due to wear of the stamper.

In view of the above, it will be apparent to those skilled in the artfrom this disclosure that there exists a need for an improved a methodfor manufacturing a base member. This invention addresses this need inthe art as well as other needs, which will become apparent to thoseskilled in the art from this disclosure.

SUMMARY OF THE INVENTION

It is an object of the present invention to be able to discover impropersupply soon and by a simple method when a blank is mistakenly suppliedto a precision machining apparatus corresponding to the wrong model.

According to a first aspect, a method for manufacturing a base member isa method for manufacturing a base member on which a plurality of membersare mounted, in which a plurality of kinds of material (or they arecalled blanks) are machined according to a machining program thatdiffers for each type of materials. The method includes the followingsteps.

A preparation step of providing a display portion with a different shapefor each type of material

A machining step of machining the material according to a machiningprogram

A machining operation step of performing an operation for machining thedisplay portion as part of the machining step, and thereby making itpossible to determine whether or not the material has been machined inthe proper combination according to the corresponding machining program

With this method, since it is possible to determine whether or not thematerial has been machined according to the corresponding machiningprogram, if the material is mistakenly supplied to a precision machiningapparatus corresponding to the wrong model, the missupply can bedetected early on by a simple method.

It is preferable that, in the machining operation step, an operation isperformed for machining the display portion by a different method foreach type of machining programs.

It is preferable that, in the machining operation step, a normal mark isrecorded to the display portion when the material is machined in theproper combination according to the corresponding machining program.

With this method, a normal mark is recorded when the material ismachined in the proper combination. Therefore, it can be determined fromthe presence or absence of the normal mark whether or not thecombination of material and machining program is the proper one.

It is preferable that, in the preparation step, a model identificationportion is provided to the display portion for identifying the type ofmaterial, and in the machining operation step, the normal mark isrecorded by machining the model identification portion and/or a portionof the display portion other than the model identification portion.

With this method, it can be determined from the presence or absence ofthe normal mark whether or not the combination of material and machiningprogram is the proper one, and furthermore the type of material can bedetermined by the model identification portion.

It is preferable that, in the machining operation step, an abnormal markis recorded to the display portion when the material is machinedaccording to a machining program other than the corresponding machiningprogram.

With this method, an abnormal mark is recorded when the material is notmachined in the proper combination. Therefore, it can be determined fromthe presence or absence of the abnormal mark whether or not thecombination of material and machining program is the proper one.

It is preferable that, in the preparation step, a model identificationportion is provided to the display portion for identifying the type ofmaterial, and in the machining operation step, the abnormal mark isrecorded by machining the model identification portion and/or a portionof the display portion other than the model identification portion.

With this method, it can be determined from the presence or absence ofthe abnormal mark whether or not the combination of material andmachining program is the proper one, and furthermore the type ofmaterial can be determined by the model identification portion.

It is preferable that the method further includes a judgment step ofdetermining, on the basis of the state of the display portion, whetheror not the material was machined according to the correspondingmachining program.

With this method, it can be determined in the judgment step whether ornot the combination of the material and the machining program is theproper one.

It is preferable that, in the judgment step, a reference mark in areference location is also used.

With this method, since the reference mark is used in the judgment stepto determine whether or not the material has been machined according tothe corresponding machining program, judgment precision can be improved.

It is preferable that the method further includes a formation step offorming the reference mark near the display portion, as part of themachining step.

It is preferable that, in the machining operation step, a plurality oflocations are machined within the display portion.

With this method, whether or not the material has been machinedaccording to the corresponding machining program can be determined fromthe combination of machined locations.

It is preferable that, in the machining operation step, part of thesurface of the material is made to be different in its shape orproperties.

With this method, since image recognition technology is used todetermine whether or not the combination of the material and themachining program is the proper one, judgment is easier. The phrase “thesurface shape is made to be different” as used here encompasses makingholes, planing, forming grooves, and so forth. The phrase “the surfaceproperties are made to be different” encompasses changing the color,surface roughness, and so forth by means of cutting, painting thesurface, and so forth.

It is preferable that, in the machining operation step, the color ofpart of the display portion is made to be different from the color ofthe other part of the display portion.

It is preferable that, in the machining operation step, the surface ofpart of the display portion is peeled off.

It is preferable that, in the machining operation step, the surface ofpart of the display portion is tinted or painted.

It is preferable that, in the machining operation step, the surfaceroughness of part of the display portion is made to be different fromthe surface roughness of the other part of the display portion.

According to a second aspect, a method for manufacturing a motorincludes the method for manufacturing a base member pertaining to thefirst aspect, and a mounting method for mounting various componentsmounted to the base member.

With this method, a base member that has been precision machined by amachining program other than the corresponding machining program will bedifficult to utilize in subsequent steps, so it is less likely that amistakenly machined base member will be assembled into a motor.

According to a third aspect, a method for manufacturing an informationapparatus includes the method for manufacturing a motor as described,and an assembly method for assembling into the motor a rotating bodythat is rotated by the motor, and an information transmission device fortransmitting information in conjunction with the rotating body areassembled into the motor.

With this method, base member that has been precision machined by amachining program other than the corresponding machining program will bedifficult to utilize in subsequent steps, so it is less likely that amistakenly machined base member will be assembled into an informationapparatus.

According to a fourth aspect, a base member is a base member on which aplurality of components are mounted. The base member includes a basemain body and a display portion that displays a state by which it can bedetermined whether or not the base main body has been machined in theproper combination according to the corresponding machining program. Thephrase “state by which it can be determined” refers to a state obtaineddepending on the combination of the structure of the material and themachining by machining program, and encompasses both a case when thedisplay portion has actually been machined by the machining program, anda case in which it has not.

With this base member, since a state by which it can be determinedwhether or not the base main body has been machined in the propercombination according to the corresponding machining program is recordedto the display portion, if the base main body is mistakenly supplied toa precision machining apparatus corresponding to the wrong model, themissupply can be detected early on by a simple method.

It is preferable that a model identification portion is provided to thedisplay portion for identifying the type of base main body. Theabove-mentioned state is achieved by the model identification portionand/or a portion of the display portion other than the modelidentification portion.

With this base member, whether or not the proper machining has beenperformed can be determined from the above-mentioned state, andfurthermore the type of material can be determined from the modelidentification portion.

According to a fifth aspect, a motor includes a base member manufacturedby the method for manufacturing a base member pertaining to the firstaspect, or the base member as described and a rotation apparatus that isinstalled on the base member.

With this motor, a base member that has been precision machined by amachining program other than the corresponding machining program can beeasily detected. Therefore, it is less likely that a mistakenly machinedbase member will be assembled into a motor.

According to a sixth aspect, an information apparatus includes the motoras described, a rotating body that is rotated by the motor, and aninformation transmission device for transmitting information inconjunction with the rotating body.

With this information apparatus, a base member that has been precisionmachined by a machining program other than the corresponding machiningprogram can be easily detected. Therefore, it is less likely that amistakenly machined base member will be assembled into an informationapparatus.

With the method for manufacturing a base member pertaining to thepresent aspect, it is possible to determine whether or not a materialhas been machined according the corresponding machining program, so ifthe material mistakenly is supplied to a precision machining apparatuscorresponding to the wrong model, the missupply can be detected early onby a simple method.

These and other objects, features, aspects and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing detailed description, which, taken in conjunction with theannexed drawings, discloses a preferred embodiment of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is simplified external side views of two kinds of base plates inthe first embodiment of the present invention;

FIG. 2 consists of diagrams illustrating the shape of the displayportion on the external side of different types of base plate;

FIG. 3 consists of diagrams illustrating the shape of the displayportion on the internal side of different types of base plate;

FIG. 4 is a flowchart of the steps for assembling a motor in the firstembodiment of the present invention;

FIG. 5 is a schematic cross section illustrating the display portionmachining and non-machining operation in the first embodiment of thepresent invention;

FIG. 6 is a binarized image illustrating the machined state of thedisplay portion;

FIG. 7 is a binarized image illustrating the unmachined state of thedisplay portion;

FIG. 8 is a schematic cross section illustrating the display portionmachining operation in the second embodiment;

FIG. 9 is a schematic cross section illustrating the display portionmachining operation in the third embodiment;

FIG. 10 is a schematic cross section illustrating the display portionmachining operation in the fourth embodiment;

FIG. 11 is a schematic cross section illustrating the display portionmachining operation in the fifth embodiment;

FIG. 12 is a partial plan view illustrating the machined state of thedisplay portion in the fifth embodiment;

FIG. 13 is a schematic cross section illustrating the display portionmachining operation in the sixth embodiment;

FIG. 14 is a binarized image illustrating the machined state of thedisplay portion in the sixth embodiment;

FIG. 15 is a schematic cross section illustrating the display portionnon-machining operation in the seventh embodiment;

FIG. 16 is a schematic cross section illustrating the display portionnon-machining operation in the eighth embodiment;

FIG. 17 is a schematic diagram illustrating the display portionmachining operation in the ninth embodiment;

FIG. 18 is a schematic diagram illustrating the display portionmachining operation in the tenth embodiment;

FIG. 19 consists of diagrams illustrating the machined state of thedisplay portion machining operation in the twelfth embodiment;

FIG. 20 consists of diagrams illustrating the machined state of thedisplay portion machining operation in the thirteenth embodiment; and

FIG. 21 is a schematic cross section of a hard disk drive as an exampleof the information apparatus in an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Selected embodiments of the present invention will now be explained withreference to the drawings. It will be apparent to those skilled in theart from this disclosure that the following descriptions of theembodiments of the present invention are provided for illustration onlyand not for the purpose of limiting the invention as defined by theappended claims and their equivalents.

FIG. 21 is a schematic cross section of a hard disk drive as an exampleof the information apparatus in an embodiment of the present invention.The hard disk drive 2 has a housing comprising a base plate 11 and acover plate 3. The hard disk drive 2 has a spindle motor 4 and anactuator 8 on the base plate 11 inside the sealed housing. The actuator8 is a mechanism for driving heads 9. In this embodiment, two magneticdisks 5 and 6 are mounted on the spindle motor 4. While the spindlemotor 4 rotates and causes the magnetic disks 5 and 6 to rotate, theactuator 8 operates the heads 9 to record or reproduce information.

As mentioned above, the spindle motor 4 and the actuator 8 are mountedon the base plate 11. Therefore, the base plate 11 has a structure forattaching various components. Although it is depicted in FIG. 21 ashaving a flat shape, the structures for attaching the various componentsmay have mutually different heights.

First Embodiment

FIG. 1 consists of simplified external side views of two kinds of baseplates made by aluminum die casting in the first embodiment of thepresent invention. In order to prevent the generation of outgas, etc.,after the die casting of the base plate, its surface is coated byelectro deposition of a black epoxy resin, after which this is baked toform a coating film that also serves as an insulating coating. The“external sides” referred to here are the faces on the outside of thehousing. The base plate 11 is shown on the left, and a base plate 31 isshown on the right. The base plate 11 is a plate that belongs to a modelA, while the base plate 31 is a plate that belongs to a model B. The“model” in the following description refers to the type of hard diskdrive, and saying that the models are different means that thestructures of the devices are different. Therefore, the structures ofthe base plates belonging to different models are mutually different.

In the drawings, the various types of hatching indicate precisionmachined faces. Hatching with a single line indicates machined regionsof a common shape, cross-hatching indicates machined regions whose shapeis specific to the model, and hatching with a double line indicatesperforated regions formed during casting.

Various structures are formed on the external side 12 a of a plate mainbody 12 of the base plate 11. For example, a plurality of HDD attachmentreference faces 14 are formed around the outer edge of the plate mainbody 12. Also, two connector fixing portions 15 and a connectorinsertion through-hole 16 are formed in the plate main body 12. Alsoshown in the drawings is a lower end reference portion 13 for a spindlemotor.

Various structures are formed on the external side 32 a of a plate mainbody 32 of the base plate 31. For example, a plurality of HDD attachmentreference faces 34 are formed around the outer edge of the plate mainbody 32. Also, two connector fixing portions 35 and a connectorinsertion through-hole 36 are formed in the plate main body 32. Alsoshown in the drawings is a lower end reference portion 33 for a spindlemotor.

Thus, the base plate 11 and the base plate 31 have roughly the samestructures, but as is clear from the drawings, their positions and sizesas well as their heights of the structures are different. In thedescription of the present invention, saying that the structures aredifferent for each model encompasses a case when only some of thestructures are different.

Furthermore, a display portion 17 is formed on the base plate 11. Thedisplay portion 17 is the rectangular region indicated by broken linesin the drawing. The display portion 17 is made up of a mark recordingportion 18 and the remaining portion 19. The mark recording portion 18is divided into a plurality of regions as indicated by the chain linesin the drawing. In this embodiment, the matrix consists of two rows andfour columns, so that a total of eight regions are formed. With the baseplate 11, a model identification portion 21 is formed in the region ofthe first row and first column of the mark recording portion 18. Themodel identification portion 21 is a convex portion as shown in FIG. 5,and forming it in this region indicates that this base plate goes to themodel A. In this embodiment, the model identification portion 21 has atrapezoidal cross section, and the upper face has a diameter of 1.0 to1.5 mm and a height of approximately 0.2 mm. The pitch of the regions is1.0 to 1.5 mm. A reference mark position 20 is indicated in theremaining portion 19 of the display portion 17. The size of the modelidentification portion 21 may be suitably changed as needed.

A display portion 37 is formed on the base plate 31. The display portion37 is the rectangular region indicated by broken lines in the drawing.The display portion 37 is made up of a mark recording portion 38 and theremaining portion 39. The mark recording portion 38 is divided into aplurality of regions as indicated by the chain lines. In thisembodiment, the matrix consists of two rows and four columns, so that atotal of eight regions are formed. With the base plate 31, a modelidentification portion 41 is formed in the region of the first row andsecond column of the mark recording portion 38. The model identificationportion 41 is a convex portion, as is the model identification portion21, and forming it in this region indicates that this base plate goes tothe model B. A reference mark position 40 is indicated in the remainingportion 39 of the display portion 37.

The broken lines or chain lines indicating the display portion and themark recording portion may protrude as ridge lines, or may not be thereat all. Further, the regions of the mark recording portion may beindicated by the intersections of crossed lines.

FIG. 2 consists of diagrams illustrating the shape of the displayportion on the external side of different types of base plate. In modelsA to H, the model identification portion is formed in different regionswithin the mark recording portion. These diagrams indicate a state inwhich precision machining of the external sides is complete. Therefore,a reference mark 20 a has been pre-drilled at the reference markposition 20, and the model identification portions are in a state ofhaving been machined (such as a state in which the coating has beenremoved to expose the base material), which will be described later.

FIG. 3 consists of diagrams illustrating the shape of the displayportion on the internal side of different types of base plate. Thedisplay portion 42 is the rectangular region indicated by broken linesin the drawing. The display portion 42 is made up of a mark recordingportion 43 and the remaining portion 44. The mark recording portion 43is divided into a plurality of regions as indicated by the chain lines.In this embodiment, the matrix consists of two rows and four columns, sothat a total of eight regions are formed. The reference mark position isthe same on the internal side of the base plate as on the external side,but the model identification portion is not formed on the mark recordingportion 43, and the mark recording portion 43 is flat overall. Thisdrawing indicates a state in which the precision machining of theinternal side is complete. Therefore, a reference mark 46 a is formed atthe reference mark position, and a pre-drill 45 is formed in a specificregion of the mark recording portion 43. The pre-drill 45 is, forexample, a portion where the coating has been removed to expose the basematerial.

FIG. 4 is a flowchart of the steps for assembling a motor in the firstembodiment of the present invention. The following description will beof the manufacture and precision machining of the base plate 11 (modelA).

In step S1 (preparation step), a blank of the base plate 11 is aluminumdie-cast. Blanks of different shapes are obtained for each model here.In the casting of these blanks, the model identification portion 21 ofthe mark recording portion 18 is formed by the casting mold. The blankmay be manufactured by injection molding, compression molding,sintering, forging, press working, or the like, as dictated by thematerial.

In step S2, both sides of the blank are given an insulating blackcoating by electro deposition coating. As a result, as shown in FIG. 5,for example, a coating 12 b is formed on the surface of the blank. Anepoxy-based paint may be applied by electro deposition coating, and ifthe blank is composed of a copper alloy or iron sheet, it may be platedwith chromium or nickel. The coating may also be applied by vapordeposition or sputtering.

In step S3 (machining step), the external side of the blank is subjectedto precision machining. More specifically, the motor attachment face orthe like is precision machined with a machining center or the like onthe basis of a machining program according to the model.

In step S3, as part of the machining step, a machining operation stepfor making it possible to determine whether or not the blank has beenmachined in the proper combination according to the correspondingmachining program is further performed by performing an operation ofmachining the display portion 17 by a different method for eachmachining program. In the machining operation step, as shown in FIG. 5,a drill 1 with a pointed tip is lowered to a specific height at theposition of the model identification portion for the blank correspondingto the model of the machining program in question. As a result, when theblank for model A is machined by the machining program for model A, asshown on the left side in FIG. 5, the drill 1 machines the modelidentification portion 21, and a pre-drill 21 a (the portion where thecoating 12 b is removed to reveal the aluminum substrate) is formed as anormal mark. On the other hand, when a blank for model A is machined bythe machining program for model B, for example, as shown on the rightside in FIG. 5, the drill 1 does not machine the model identificationportion 21. That is, the model identification portion is machined whenthere is the proper combination of blank and machining program, and isnot machined otherwise. The lowest point to which the drill 1 descendsis a position at which the model identification portion will be cut, butthe surface of the rest of the surrounding flat portion is not cut.Therefore, the rest of the region of the mark recording portion 18 isnot cut when the combination is not the proper one.

The drill 1 also performs reference pre-drilling. More specifically,center forming of the reference mark position 20 is performed to formthe reference mark 20 a.

The diameter of the mark formed at the model identification portion 21is preferably from 0.4 to 0.6 mm. If it is less than 0.4 mm, it will bedifficult to distinguish from scattered reflection caused by microscopicbumps on the blank.

Meanwhile, if the diameter of the model identification portion itself ismade sufficiently small, it will be possible to determine the shapeprecision of blank casting fin and so forth. More specifically, when ablank with casting fin or the like is chucked, the machining positionmay be significantly offset from the intended position, and if thepre-drill center position deviates too much from the modelidentification portion center, then the pre-drill will not be formed atthe model identification portion.

In step S4, the internal side of the blank is precision machined. Inthis embodiment, the external and internal side machining is carried outwith separate precision machining apparatuses. In the internal sidemachining step, as shown in FIG. 3, model information expressing theinternal side machining program itself is simultaneously machined bypre-drilling or the like.

In step S5, the display portion on the external side of the blank isread. This operation is performed by an image recognition apparatusincluding a camera and a computer capable of image processing. Thepre-drill 21 a reveals the aluminum substrate, while leaving thesurrounding black insulating coating intact, so the contrast between thetwo is high, affording reliable recognition.

FIG. 6 is a binarized image illustrating the machined state of thedisplay portion. As is clear from the diagram, the machined referencemark and the machined mark are recognized as two white circles. In thiscase, it can be determined that the combination of blank and machiningprogram is the proper one, and the model name can also be determined.

Here, the reference mark is formed at a position close to the mark,which makes it easy to read the mark coordinates. In particular, ifthere is some kind of abnormal bump or the like on the blank that causesan abnormality in the reflective state, there is the possibility that itwill be misrecognized as a mark, but the misrecognition rate can belowered by forming a distinct reference mark and using it as a referenceto process as noise anything away from the relative position where themark is supposed to be. This not only tells if the combination iscorrect, but also allows model identification to be carried outaccurately. Furthermore, even if there is deformation or casting fin atthe positioning portion used for fixing to the image recognitionapparatus, and the overall position is offset, as long as the referencemark can be recognized, the model identification portion misrecognitionrate will be reduced.

FIG. 7 is a binarized image illustrating the unmachined state of thedisplay portion. As is clear from the diagram, only the machinedreference mark is displayed as a white circle. In this case, it can bedetermined that the combination of blank and machining program is notthe proper one.

In step S6 judgment step), the mark recording portion 43 on the internalside of the blank is read, the result of this reading is subjected toimage processing, and the model information for the external side ischecked to see if it matches the model information for the internalside. If the model information for the machining program on the externalside coincides with the model information for the machining program onthe internal side, it is determined that machining programs for theblank and the internal and external sides are in complete agreement.

In this embodiment, the marks on both sides are read by turning the baseplate over, but two reading sensors may be provided so that both sidescan be read at the same time.

In step S7, any irregular products are eliminated. More specifically,this applies to when the combination of the blank model information andthe machining program model information was not the proper one in stepS5, or when the model information for the external side did not matchthe model information for the internal side in step S6.

In step S8, manufacturing information (manufacturing lot number, date,machining apparatus information, and other such information necessaryfor tracing) is laser etched on the external side of the blank as atwo-dimensional barcode.

In step S9, motor assembly is carried out. More specifically, thespindle motor 4 and the actuator 8 are attached to the base plate 11 tocomplete the hard disk drive.

Pre-shipment inspection is performed in step S10, and in step S11 thetwo-dimensional barcode is read and recorded to the productionmanagement database. After the above-mentioned final check, the productis shipped in step S12. The two-dimensional barcode does not necessarilyhave to be formed.

With this method, it is possible to determine whether or not a materialhas been machined according to the corresponding machining program, sowhen a material is mistakenly supplied to a precision machiningapparatus corresponding to the wrong model, the missupply can bedetected early on by a simple method. In particular, when the materialhas been properly machined, a mark indicating this is recorded, sowhether or not the combination of material and machining program is theproper one can be determined from the presence or absence of this mark.Furthermore, the type of material can be determined from the modelidentification portion.

With a completed hard disk drive, since the display portion 17 is formedon the external side 12 a of the base plate 11, whether the device ispassable or not can be determined right away. When the display portion17 is on the internal side of the base plate, it cannot be checkedwithout breaking the seal, in which case the hard disk drive has to betaken apart.

The step of reading the mark on the external side may be performedimmediately after the external side machining. Also, the reading of themark on the external side may be performed visually by a human.

If the precision machining of the external and internal sides of thebase plate is carried out simultaneously by the same machining programdevice, there is no need to form the display portion 42 on the internalside during casting of the blank in step S1, there is no need formachining the display portion 42 in the internal side machining in stepS4, nor is there any need for the entire step S6.

The model identification portion on each base plate is not limited to asingle one, and a plurality of model identification portions may becombined. However, it is preferable to keep the number of modelidentification portions consistent for all models. This is because inbit management the number of model identification portions will not beconsistent, which poses problems when the right and wrong judgment isperformed visually.

Second Embodiment

FIG. 8 is a schematic cross section illustrating the display portionmachining operation in a second embodiment. FIG. 8A is before machining,and FIG. 8B is after machining. In this embodiment, the surface of themodel identification portion 21 is cut away and flattened with an endmill. As a result, the exposed aluminum surface 22 becomes the normalmark.

Third Embodiment

FIG. 9 is a schematic cross section illustrating the display portionmachining operation in a third embodiment. FIG. 9A is before machining,and FIG. 9 b is after machining. In this embodiment, the base plateincludes a sheet metal chassis, a model identification portion 21′ iscut away with an end mill, and a hole 23 is formed as the normal mark.In this case, judgment can also be carried out with transmitted light.

The method for machining the mark is not limited to cutting, and mayinstead entail welding, deposition, or another such step, or may bepress working or another type of plastic deformation. In this case,after blank manufacture, other machining steps may be included offline.

Fourth Embodiment

FIG. 10 is a schematic cross section illustrating the display portionmachining operation in a fourth embodiment. In this embodiment, thesurface of a model identification portion 51 is coated with paint 53using a dispenser 52. The color of the paint is different from the colorof the blank surface. As a result, a tinted portion 54 is formed as thenormal mark on the surface of the model identification portion 51.

A fluorescent paint may be used here, in which case there is no need forit to be a different color from that of the blank, and it can bedetected easily when irradiated with a black light.

Fifth Embodiment

FIG. 11 is a schematic cross section illustrating the display portionmachining operation in a fifth embodiment. FIG. 12 is a partial planview illustrating the machined state of the display portion in the fifthembodiment.

A model identification portion 55 in the form of a recess is formed inthe blank. As a stamper 56 descends and approaches the modelidentification portion 55, the area around the model identificationportion 55 is coated with paint 57 from the stamper 56, forming anannular tinted portion 58 as the normal mark. If the combination is notthe proper one, a tinted portion in which the internal portion is alsopainted is formed as an abnormal mark.

With this embodiment, the normal mark is recorded when the combinationis correct, and the abnormal mark is recorded when the combination isincorrect.

A fluorescent paint may be used here, in which case there is no need forit to be a different color from that of the blank, and it can bedetected easily when irradiated with a black light.

In addition to the painting and stamping discussed above, engraving mayalso be performed.

Sixth Embodiment

FIG. 13 is a schematic cross section illustrating the display portionmachining operation in a sixth embodiment. FIG. 14 is a binarized imageillustrating the machined state of the display portion in the sixthembodiment.

A model identification portion 60 is formed on a plate main body 59. Themodel identification portion 60 is a concave portion that is lower thanthe flat surrounding face. Further, a coating 59 a is formed on thesurface of the plate main body 59. A drill 25 has a pointed tip, and theoutside diameter of the tip is greater than the outside diameter of themodel identification portion 60.

When the drill 25 is lowered, it cuts the bottom 61 and shoulder 62 ofthe model identification portion 60, and a center circular portion 63and an annular portion 64 are respectively formed as normal marks. As aresult, as shown in FIG. 14, image processing produces an imageincluding a white ring and a small white circle in the middle of thisring, which confirms that the combination is correct. If the combinationis incorrect, the flat face is cut away and a circular portion (notshown) is formed as an abnormal mark.

In this embodiment, normal marks are recorded when the combination iscorrect, and an abnormal mark is recorded with the combination isincorrect.

Seventh Embodiment

FIG. 15 is a schematic cross section illustrating the display portionnon-machining operation in a seventh embodiment. A display portion 66 isformed in a plate main body 65. The display portion 66 is a convexregion that is higher than the flat face, and has a plurality of regionsas shown in the first embodiment. A model identification portion 67 isformed in one of the regions of the display portion 66. The modelidentification portion 67 is recessed lower than the other part of thedisplay portion 66, and is about the same height as the flat face.

During precision machining, the drill 1 forms a reference mark 68 anddescends at a different location depending on the type of machiningprogram in the display portion 66. Therefore, if the blank modelinformation matches the machining program model information, as shown inthe drawings, the drill 1 goes inside the model identification portion67. As a result, the other portion of the display portion 66 is notmachined. If the combination is incorrect, on the other hand, the drill1 ends up machining a portion of the display portion 66 other than themodel identification portion 67. The above allows the combination to bedeemed abnormal if there is a machining trace in a portion of thedisplay portion 66 other than the model identification portion 67.

With this method, an abnormal mark is recorded if the material has notbeen machined properly. Therefore, whether or not the combination ofmaterial and machining program is correct can be determined from thepresence or absence of an abnormal mark. Furthermore, the type ofmaterial can be determined by the model identification portion.

Also, no mark is recorded on the material if the material has beenproperly machined. However, in this case, that the combination ofmaterial and machining program is correct is indicated by the fact thatthe display portion of the base plate has not been machined.

In this embodiment, machining for mark formation is not performed whenthe combination is correct, and machining for mark formation isperformed when the combination is incorrect. Since machining is thus notperformed when the combination is correct, drill wear is prevented andcutting dust is reduced.

Furthermore, since the reference mark 68 is formed, it is easy to tellwhether or not the combination is correct. With the above method, sinceno mark is formed when the combination is correct, if the blank has notbe mounted accurately in the image recognition apparatus, the mark maynot be recognizable even if one has been formed. In this case, a statein which the combination is correct and no mark has been formed cannotbe distinguished from a state in which the combination is incorrect anda mark has been formed, but that mark cannot be recognized. In view ofthis, whether or not a mark has been formed at the specific markformation position can be determined more reliably by forming areference mark.

Eight Embodiment

FIG. 16 is a schematic cross section illustrating the display portionnon-machining operation in an eighth embodiment.

A coating 69 a is formed on the surface of a plate main body 69. Adisplay portion 70 is formed on the plate main body 69. The displayportion 70 is a flat region, and has a plurality of regions as shown inthe first embodiment. A model identification portion 71 is formed in oneof the regions of the display portion 70. The model identificationportion 71 is convex, protruding beyond the surrounding flat face.

During precision machining, the drill 1 forms a reference mark 72 anddescends on the entire region of the blank, other than the modelidentification portion 71, where the model information coincides withthe corresponding machining program, depending on the type of machiningprogram in the display portion 70. Therefore, if the blank modelinformation matches the machining program model information, as shown inthe drawing, the drill 1 repeats the descending operation so as to avoidthe model identification portion 71 (so that the other portion ishypothetically machined). As a result, the model identification portion71 is not machined. If the combination is wrong, on the other hand, thedrill 1 ends up cutting away the model identification portion 71. Theabove allows the combination to be deemed abnormal if there is amachining trace in the model identification portion 71 of the displayportion 70.

With this method, an abnormal mark is recorded if the material has notbeen machined properly. Therefore, whether or not the combination ofmaterial and machining program is correct can be determined from thepresence or absence of an abnormal mark.

Also, no mark is recorded on the material if the material has beenproperly machined. However, in this case, that the combination ofmaterial and machining program is correct is indicated by the fact thatthe display portion of the base plate has not been machined.

In this embodiment, machining for mark formation is not performed whenthe combination is correct, and machining for mark formation isperformed when the combination is incorrect. Since machining is thus notperformed when the combination is correct, drill wear is prevented andcutting dust is reduced.

Furthermore, since the reference mark 72 is formed, it is easy to tellwhether or not the combination is correct.

Ninth Embodiment

FIG. 17 is a schematic diagram illustrating the display portionmachining operation in a ninth embodiment. A coating 73 a is formed onthe surface of a plate main body 73. A display portion 74 is formed onthe plate main body 73. The display portion 74 is a flat region, and hasa plurality of regions as shown in the first embodiment. A modelidentification portion 75 is formed in one of the regions of the displayportion 74. The model identification portion 75 is convex, protrudingbeyond the surrounding flat face.

During precision machining, the drill 1 with a pointed tip successivelycuts away all of the surface of the region other than the modelidentification portion 75 in the display portion 74. Therefore, if theblank model information matches the machining program model information,machining traces 76 a to 76 d are formed in the region other than themodel identification portion 75. These machining traces are all the samesize. If the blank model information does not match the machiningprogram model information, a plurality of regions other than the modelidentification portion 75 are machined, and in addition the modelidentification portion 75 is also machined. In this case the size of themachining trace of the model identification portion 75 will be differentfrom the size of the machining traces of the other regions (in thisembodiment, the machining trace of the model identification portion arelarger). The above allows the combination to be deemed abnormal if evenone of the machining traces is a different size.

In this case, either a mark indicating a normal combination or a markindicating an abnormal combination is always recorded. Morespecifically, a plurality of marks are formed in just the region otherthan the model identification portion if the combination is normal, anda plurality of marks are formed in both the model identification portionand the other region if the combination is abnormal.

The model identification portion may be concave, in which case if thecombination is abnormal, the machining trace in the model identificationportion will be smaller than the machining traces in the other region orthe model identification portion will not be machined.

A plurality of model identification portion may also be formed.

Also, a reference mark may not be formed in this embodiment.

Tenth Embodiment

FIG. 18 is a schematic diagram illustrating the display portionmachining operation in a tenth embodiment. A display portion 80 isformed on a plate main body 79. The display portion 80 has a pluralityof concave regions 82 a to 82 d. A model identification portion 81 isformed on the display portion 80. The model identification portion 81 isthe same height as the surrounding flat face of the display portion 80.

In the machining operation step, a drill 1 with a pointed tip is loweredto a specific height at the position of the model identification portionfor the blank corresponding to the model of the machining program inquestion. As a result, when the blank for model A is machined by themachining program for model A, the drill 1 machines the modelidentification portion 81, and a pre-drill 81 a is formed as a normalmark.

Eleventh Embodiment

In the first to tenth embodiments above, the operations for machiningthe display portion were carried out by a different method for everymachining program. However, the operations for machining the displayportion may be the same for all the machining programs. In this case,though, a machined portion with a different shape for every model mustbe provided to the display portion of the plate. Also, upon the stepwhich follows the completion of the operation for machining the displayportion, it is preferable to read the state of the display portion byimage recognition and to specify the type of blank. This makes itpossible to determine reliably whether or not a blank that has alreadybeen machined was machined according to the corresponding machiningprogram. Or, when a blank is machined after the display portion has beenmachined, the blanks can be reliably sorted by model. Or, when a blankis machined after the display portion has been machined, the program canbe flexibly switched to one corresponding to the blank model accordingto a blank whose display portion has been read and that has been set inthe machining apparatus.

An example will be described through reference to FIG. 5 of the firstembodiment. In the machining operation step, the drill 1 descends to themachining position in the entire region of the display portion. Thedrill 1 machines the model identification portion 21 to form thepre-drill 21 a (the portion where the coating 12 b is removed to revealthe aluminum substrate).

Next, the display portion on the external side of the blank is read byan image recognition apparatus including a camera and a computer capableof image processing, and image recognition is performed. In this imagerecognition, the type of blank is specified on the basis of the placewhere the pre-drill has revealed the aluminum substrate. Whether or notthe blank has been machined according to the corresponding machiningprogram is thereby determined. Or, when a blank is machined after thedisplay portion has been machined, the blanks can be reliably sorted bymodel. Or, when a blank is machined after the display portion has beenmachined, the program can be flexibly switched to one corresponding tothe blank model according to a blank whose display portion has been readand that has been set in the machining apparatus.

Twelfth Embodiment

The configuration may be such that information that is meaningful to ahuman or a machine appears on the surface when the combination iscorrect in order to create a state in which it is possible to determinewhether or not a blank has been machined in the proper combinationaccording to the corresponding machining program. “Meaningfulinformation” here encompasses text, graphics, shapes, patterns, andcombinations thereof that can be read and distinguished by a human or amachine (or within a range predetermined according to the design). Also,“meaningful information” may be various kinds of code, such as abarcode, a two-dimensional code, text, or graphics.

An example of machining over a preformed pattern will be describedthrough reference to FIGS. 19A to 19C.

A model name “AB2” is formed in bold relief, etc., on the displayportion of the blank as shown in FIG. 19A. Then, during the machiningoperation, the machining program moves the tool over the relief, etc.,to cut away or tint the surface so as to write the specific model name.As a result, if the combination is correct, the correct model name showsup as in FIG. 19B, but if the combination is incorrect, the writing willappear strange as shown in FIG. 19C. FIG. 19C shows a case of anincorrect combination when the machining operation for model “AB1” hasbeen applied to a blank for model “AB2”.

The pattern or shape formed on the display portion of the blank, or thepattern formed in the machining of these, need not be continuous lines.For instance, it may be dot text, symbols, or picture text.

Thirteenth Embodiment

The configuration may be such that information that is meaningful to ahuman or a machine appears on the surface when the combination iscorrect in order to create a state in which it is possible to determinewhether or not a blank has been machined in the proper combinationaccording to the corresponding machining program. “Meaningfulinformation” here encompasses text, graphics, shapes, patterns, andcombinations thereof that can be read and distinguished by a human or amachine (or within a range predetermined according to the design). Also,“meaningful information” may be various kinds of code, such as abarcode, a two-dimensional code, text, or graphics.

A machining example in which a further pattern is added to a preformedpattern will be described through reference to FIGS. 20A to 20C.

A plurality of holes or recesses, indicated by black, are formed in thedisplay portion of the blank as shown in FIG. 20A. These holes make uppart of the original model name “AB2”, but at this stage, since holes orrecesses have yet to be formed at a plurality of locations, a humanlooking at them will not recognize them as the text “AB2”. Then, duringthe machining operation, the machining program lowers a drill and formsthe plurality of holes or recesses so that the model name shows up. As aresult, if the combination is correct, the proper model name will showup as in FIG. 20B, but if the combination is incorrect, a meaninglessletter will show up as in FIG. 20C. FIG. 20C shows a case of anincorrect combination when the machining operation for model “AB1” hasbeen applied to a blank for model “AB2”.

Bumps, or marks made by stamping or the like, or a combination of these,may be used instead of holes or recesses to form the meaningfulinformation.

Other Embodiments

In the first embodiment, a reference mark was formed during themachining operation, and the reference mark was also used in thejudgment step. However, the reference mark may be formed not during themachining operation, but before that, or a structure having anotherfunction can be utilized as a reference mark. For instance, a VCM pivotsupport shaft fixing hole, or a threaded hole for drive fixing providedto a housing may be utilized as a reference mark.

The number of regions in the mark recording portion, and their layout,are not limited to the above embodiments. For instance, the number ofregions of the mark recording portion may be changed according to thenumber of models.

Cutting may be performed not by pre-drilling, but by forming a groove.

The following method is possible, for example, when no insulating blackcoating is provided. The blank surface is subjected to sandblasting, forexample, to increase the surface roughness. When this blank undergoesprecision machining, the mark can be formed at the model identificationportion by reducing the surface roughness of the model identificationportion through cutting, coating, or the like. More specifically, thisis because the model identification portion is glossy, and the extent ofirregular reflection varies in the other portion.

A hard disk drive was used as an example of an information apparatus inthe above embodiments, but the present invention can also be applied tooptical disk devices and other such recording and reproducing devices,and to laser scanners and other such information apparatuses other thanwhat was discussed above.

Furthermore, a base plate was used as an example of the base member inthe above embodiments, but the present invention can also be applied toother members. For example, it can be applied to products in whichmembers whose basic design is similar, such as an automotive engine, atransmission, or a chassis frame, but differ slightly in form with themodel, function as a basis with which other parts are assembled tocomplete a finished product.

The method for manufacturing a base member pertaining to the presentinvention can be applied to the manufacture of hard disk drives andother such information apparatuses, and therefore has industrialapplicability.

As used herein, the following directional terms “forward, rearward,above, downward, vertical, horizontal, below and transverse” as well asany other similar directional terms refer to those directions of adevice equipped with the present invention. Accordingly, these terms, asutilized to describe the present invention should be interpretedrelative to a device equipped with the present invention.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. Furthermore, the foregoing descriptions of theembodiments according to the present invention are provided forillustration only, and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents. Thus, the scope ofthe invention is not limited to the disclosed embodiments.

1. A method for manufacturing a base member on which a plurality ofmembers are mounted, in which a plurality of kinds of material aremachined according to a machining program that differs for each type ofmaterials, said method comprising: a preparation step of providing adisplay portion with a different shape for each type of material; amachining step of machining the material according to a machiningprogram; and a machining operation step of performing an operation formachining the display portion as part of the machining step, and therebymaking it possible to determine whether or not the material has beenmachined in the proper combination according to the correspondingmachining program.
 2. The method for manufacturing a base memberaccording to claim 1, wherein, in the machining operation step, anoperation is performed for machining the display portion by a differentmethod for each type of machining programs.
 3. The method formanufacturing a base member according to claim 1, wherein, in themachining operation step, a normal mark is recorded to the displayportion when the material is machined in the proper combinationaccording to the corresponding machining program.
 4. The method formanufacturing a base member according to claim 3, wherein, in thepreparation step, a model identification portion is provided to thedisplay portion for identifying the type of material, and in themachining operation step, the normal mark is recorded by machining themodel identification portion and/or a portion of the display portionsother than the model identification portion.
 5. The method formanufacturing a base member according to claim 1, wherein, in themachining operation step, an abnormal mark is recorded to the displayportion when the material is machined according to a machining programother than the corresponding machining program.
 6. The method formanufacturing a base member according to claim 5, wherein, in thepreparation step, a model identification portion is provided to thedisplay portion for identifying the type of material, and in themachining operation step, the abnormal mark is recorded by machining themodel identification portion and/or a portion of the display portionother than the model identification portion.
 7. The method formanufacturing a base member according to claim 1, further comprising ajudgment step of judging, on the basis of the state of the displayportion, whether or not the material was machined according to thecorresponding machining program.
 8. The method for manufacturing a basemember according to claim 7, wherein, in the judgment step, a referencemark in a reference location is also used.
 9. The method formanufacturing a base member according to claim 8, further comprising aformation step of forming the reference mark near the display portion,as part of the machining step.
 10. The method for manufacturing a basemember according to claim 1, wherein, in the machining operation step, aplurality of locations are machined within the display portion.
 11. Themethod for manufacturing a base member according to claim 1, wherein, inthe machining operation step, the surface of part of the display portionis made to be different in its shape or properties.
 12. The method formanufacturing a base member according to claim 11, wherein, in themachining operation step, the color of part of the display portion ismade to be different from the color of the other part of the displayportion.
 13. The method for manufacturing a base member according toclaim 11, wherein, in the machining operation step, the surface of partof the display portion is peeled off.
 14. The method for manufacturing abase member according to claim 12, wherein, in the machining operationstep, the surface of part of the display portion is tinted or painted.15. The method for manufacturing a base member according to claim 11,wherein, in the machining operation step, the surface roughness of partof the display portion is made to be different from the surfaceroughness of the other part of the display portion.
 16. A method formanufacturing a motor, comprising: the method for manufacturing a basemember according to claim 1; and a mounting method for mounting variouscomponents to the base member.
 17. A method for manufacturing aninformation apparatus, comprising: the method for manufacturing a motoraccording to claim 16; and an assembly method for assembling into themotor a rotating body that is rotated by the motor, and an informationtransmission device for transmitting information in conjunction with therotating body.
 18. A base member on which a plurality of components aremounted, the base member comprising: a base main body; and a displayportion that displays a state by which it can be determined whether ornot the base main body has been machined in the proper combinationaccording to the corresponding machining program.
 19. The base memberaccording to claim 18, wherein a model identification portion isprovided to the display portion for identifying the type of base mainbody, and the state is achieved by the model identification portionand/or a portion of the display portion other than the modelidentification portion.
 20. A motor, comprising: a base membermanufactured by the method for manufacturing a base member according toclaim 1; and a rotation apparatus that is installed on the base member.21. A motor, comprising: the base member according to claim 18; and arotation apparatus that is installed on the base member.
 22. A motor,comprising: the base member according to claim 19; and a rotationapparatus that is installed on the base member.
 23. An informationapparatus, comprising: the motor according to claim 20; a rotating bodythat is rotated by the motor; and an information transmission device fortransmitting information in conjunction with the rotating body.
 24. Aninformation apparatus, comprising: the motor according to claim 21; arotating body that is rotated by the motor; and an informationtransmission device for transmitting information in conjunction with therotating body.
 25. An information apparatus, comprising: the motoraccording to claim 22; a rotating body that is rotated by the motor; andan information transmission device for transmitting information inconjunction with the rotating body.